Means for locking firearm barrels



Sepiz. 23, 1952 c E YS|MPSON 2,611,297

MEANS FOR LOCKING FIREARM BARRELS Original Filed June 7, 1946 2 SHEETS-SHEET 1 o o HA9 Sept 23, 1952 c. E. SIMPSON MEANS FOR LOCKING FIREARM BARRELS 2 SHEETSSHEET 2 Original Filed June '7, 1946 E5011. W LM M L l hu E1111 E'I'LE Q E Mommy! Patented Sept. 23, 1952 MEANS FOR LOQK IN G FIREARM BARRELS Clarence SimpsonQWilbraham, Mass., assignor .to the UnitedStates of America as represented byjthes ecretary of War l Original application June '7, 1946, Serial 'No.

675,124. Dividecland this application December 21, 1949, Serial No. 134,311

' I 2 Claims. ((11. espi) (Granted under the act of March 3, 1883, as

amended-April 30, 1928; 370 0. G. 757) The invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment to me of any royalty thereon.

This invention relates to semiautomatic firearms having a recoiling barrel and is particularly directed to improved means for rapid barrel replacement.

This application is a division of 'my copending application for- Firearm dated J une 7, 1946; Serial No. 675,124 andnow matured into US. Patent No. 2,555,379.

Most firearms of the semiautomatic type which utilize a comparatively large caliber cartridge are of rather ponderous and complicated construction. Accordingly, it is of the utmost importance that such a firearm be relatively simple to disassemble into unit assemblies for ease in transportation. This requirement for simplicity of disassembly is also of particular importance in the problem of barrel replacement.

Accordingly, it is an object of this invention to provide in. a large caliber semiautomatic weapon an improved construction which will permit easy and rapid replacement of the barrel.

It is a further object of this invention to provide a large caliber military type of firearm which is so constructed that it'ean be rapidly and easily disassembled into two major assemblies forease in transportation.

The specific nature of the invention as wellas other objects and advantages thereof will clearly appear from a description of a preferred embodiment as shown in the accompanying drawings in which: i l v Fig, 1 is a left side perspective view showing the barrel and barrel extension assembled in the receiver with the feedway in the locked position;

Fig. 2 is a view similar to Figil' but'showing the barrel and barrel extension partially retracted from their battery position and with the-feedway in the unlocked position.

Fig. 3 showing the barrel andbarrel extensionabout to be disengaged from the receiver and showing in dotted outline the pivoting movement imparted to the barrel upon such disengagement.

Fig. 4 is a perspective fragmentary view of the left and right side plates comprising the receiver. 1

Fig. 5 is a rear end elevational view of the barrel and barrel extension.

Fig. 6 is a left side view of the barrel extension. r

Fig. 7 is a top view of the rear portion of the is a view similar'to Figsfl and 2 but 2" firearm with the feedway in the unlocked posi tion and the breech block partially retracted.

Fig. 8 is a right side elevational view of the forward'portion of the firearm showing the front barrel bearing and the recoil mechanism latch in crosssection. l r Fig. 9 is a cross-sectional view of the barrel sleeve taken along the line 9-9 in Fig. 8.

The semiautomatic weapon to'which the present invention applies is a heavy large caliber gun designed specifically for attacking armored vehicles such as tanks or the like.

' As illustrated in the drawings, there is provided an open receiver 5 comprising a bottom plate 6 and a left and right side plate designated respectively by numerals 1 and 8. A breech block assembly comprising a breech block 9 and a carrier 15 is slidably mounted in receiver 5 for longitudinal reciprocal movement between a recoiled and a counter-recoiled battery position. In the latter position, locking lugs (not shown). on breech block 9 are arranged to engage in front of similar locking lugs It provided at therear end of a substantially rectangular barrel extension 13. A barrel I2 is threadably secured at its breech end to barrel extension I3. A pair of longitudinal ribs [4 are provided on opposite sides of barrel-extension l3 and are arranged to slide ably engage in longitudinal grooves l5 extending along the interior walls of side plates 7 and 8. The forward portion of each of grooves l5 terminates in a recess I6 formed by cutting away a portion of the interior wall of side plates 1 and G and is best illustrated in Fig. 4. Recesses I6 permit disassembly of barrel extension l3 from' receiver '5 in a manner to be described;

A rectangular bar I! is slidably mounted to left side plate 1 by means of a screw l8 which passes through an elongated slot it provided in bar l7 and threadably'engages in-side plate '5. A washer 20 of greater diameter than screw l8 serves as a bearing surface for the head portion of such screw. A latch 21 is pivotally secured to the forward end of bar I! and is provided with an inwardly extending lug 22. During counter-recoil movement of barrel extension; is, a stud 23 protruding from the left side thereof is arranged to contact the rear surface of lug 22 and thereby carry bar ll forwardly as barrel I 2 and barrel extension i3 move into battery position. The front edge of lug 22 is provided with an angular cam surface 24 arranged to mate with a similarly inclined surface 25 on the rear of stud 23 so that latch 2| can be pivoted out from in front thereof to permit rearward movement of barrel until ribs [4 on barrel extension l3 clear longitudinal grooves l in side plates 1 and 8 and align with recesses I6. Thereupon, barrel extension l3 can be lifted upwardly to tilt barrel l2 and disengage fork 58 from piston rod 60. Tapered portions 31 and 38 in loop 35 of front barrel bearing 34 permits the pivoting movement shown by the dotted lines in Fig. 3. Barrel l2 can then be withdrawn entirely from bearing 34.

To reassemble the barrel or replace it with another, barrel extension [3 is first attached thereto and then placed on the top surfaces of side plates 1 and 8 slightly to the rear of recesses 16. In this position, fork 58 will engage piston rod 60 which had been previously moved slightly to the rear due to the bias of operating spring 68. Then by pushing barrel extension l3 forwardly, its weight will cause ribs I 4 to drop into recesses l6 and align with longitudinal grooves l5. Then by merely reversing the procedure outlined above, barrel I 2 can be readily assembled to receiver 5 and retained therein against disassembly by feedway 23.

Thus there is here provided a construction in which the barrel l2 and barrel extension l3 can be readily removed from the rest of the gun for transportation purposes. Reassembly of the parts into operating position is also accomplished as readily and simply as the disassembly.

I claim:

1. In a firearm, the combination of a channelshaped receiver having a longitudinal groove in either side thereof, a substantially rectangular barrel extension having a longitudinal rib on either side thereof for slidable engagement with said respective receiver groove, each of said grooves terminating at the forward end thereof in a cutaway portion of sufficient length to permit vertical passage therethrough of said barrel extension rib, a barrel fixedly secured to said barrel extension for movement therewith, a cylindrical tube extending through the front of said receiver and disposed beneath and parallel to said barrel, a spring-biased piston slidably mounted for longitudinal reciprocal movement in said tube, yoke means connecting said barrel with the rear end of said piston whereby the spring-urged movement thereof imparts counterrecoil movement to said barrel and barrel extension, a blocking member pivotally secured at one end to one side of said receiver adjacent the rear end of said cutaway portion therein and releasably latched at the other end to the opposite side of said receiver, said blocking member having an arcuate underside portion and a rearwardly adjacent rectangular recessed portion, a shoulder formed by the junction of said underside portions of said blocking member, said arcuate underside portion arranged to fit around the upper periphery of said barrel and said rectangular recessed portion arranged to provide access for said barrel extension whereby the side of said shoulder serves to stop said barrel extension and thereby said barrel in battery position, means for releasing the latched end of said blocking member from said receiver whereby pivotal movement thereof transversely of said receiver withdraws said shoulder from in front of said barrel extension thereby permitting said barrel extension to be moved forwardly until said yoke means contacts the rear end of said cylindrical tube, and retractable detent means located at the front end of said receiver for normally engaging said cylindrical tube to prevent forward movement thereof when said blocking member is rendered inoperative, all adapted and arranged whereby retraction of said detent means from engagement with said tube frees said cylindrical tube and thereby said barrel and barrel extension for simultaneous forward movement in order to align said ribs on said barrel extension with said cutaway portions in said receiver for disassembly of said barrel and barrel extension therefrom.

2. The combination defined in claim 1 wherein said cylindrical tube includes a shoulder on the underside thereof and said retractable detent means comprises a hollow screw threadably secured in said receiver adjacent the front end thereof, a cylindrical latch member slidably mounted through said screw for vertical movement into and out of engagement with said shoulder in said tube, a projecting stud on the upper portion of said latch slidably engageable in said receiver for preventing rotation of said latch in said hollow screw, spring means normally biasing said latch upwardly into engagement with said shoulder in said tube, the lower end of said latch extending downwardly out of said receiver, a fixed pin transversely mounted in said lower end of said latch and of such length as to protrude from either side thereof, and a lever loosely engageable with said depending latch end and disposed between the bottom end of said hollow screw and said fixed pin whereby pivotal downward movement of said lever about the ends of said fixed pin as a fulcrum retracts said latch member out of engagement with said shoulder in said cylindrical tube, said hollow screw being arranged to adjust and maintain the clearance between the upper end of said latch and the underside of said cylindrical tube.

CLARENCE E. SIMPSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS OTHER REFERENCES The Machine Gun (vol. 1), Eu. 0rd., U. S. N., by Lt. Col. Chinn (U. S. Superintendent of Documents). pages 484-488.

Einzelausbildung AM M. 89/Pub.

G. 42 (Manual) 

